Update function type after inserting KernelContext parameter (#8551)

Without this, there are functions with missing parameters in their type
in the IR after running the `introduceExplicitGlobalContext` pass:

```
[layout(%15)]
[export("_SV4test12outputBuffer")]
[nameHint("outputBuffer")]
let  %outputBuffer      : _     = key
[noSideEffect]
[export("_S4test7dostuffp1pi_ff")]
[nameHint("dostuff")]
func %dostuff   : Func(Float, Float)
{
block %34(
                [nameHint("f")]
                param %f        : Float,
                [nameHint("kernelContext")]
                param %kernelContext    : Ptr(%KernelContext, 0 : UInt64, 1 : UInt64)):
        let  %35        : Float = mul(%f, %f)
        let  %36        : Ptr(ConstantBuffer(%GlobalParams, DefaultLayout), 0 : UInt64, 1 : UInt64)     = get_field_addr(%kernelContext, %globalParams)
        let  %37        : ConstantBuffer(%GlobalParams, DefaultLayout)  = load(%36)
        let  %38        : Ptr(RWStructuredBuffer(Float, DefaultLayout, %20))    = get_field_addr(%37, %outputBuffer)
        let  %39        : RWStructuredBuffer(Float, DefaultLayout, %20) = load(%38)
        let  %40        : Ptr(Float)    = rwstructuredBufferGetElementPtr(%39, 1 : Int)
        let  %41        : Float = load(%40)
        let  %42        : Float = mul(%35, %41)
        return_val(%42)
}
```

Not sure why this doesn't seem to negatively affect existing targets,
but it sure is an issue for the LLVM target I'm working on. I could've
left this fix for that PR, but I want to check now if this causes any
issues with the existing targets using the CI.

This also happens with the entry point functions, where the function
type is not updated after adding `ComputeThreadVaryingInput`. This had
no effect in the C++ target because
`convertEntryPointPtrParamsToRawPtrs(irModule);` is called right after
and fixes it.

1 files changed, 6 insertions, 0 deletions

diff --git a/source/slang/slang-ir-explicit-global-context.cpp b/source/slang/slang-ir-explicit-global-context.cpp
index dd07db883..515992cee 100644
--- a/source/slang/slang-ir-explicit-global-context.cpp
+++ b/source/slang/slang-ir-explicit-global-context.cpp
@@ -564,6 +564,9 @@ struct IntroduceExplicitGlobalContextPass
                 builder.emitStore(fieldPtr, var);
             }
         }
+
+        // Update entry point function type after potentially adding parameters.
+        fixUpFuncType(entryPointFunc);
     }
 
     void replaceUsesOfGlobalParam(IRGlobalParam* globalParam)
@@ -723,6 +726,9 @@ struct IntroduceExplicitGlobalContextPass
         addKernelContextNameHint(contextParam);
         contextParam->insertBefore(firstBlock->getFirstOrdinaryInst());
 
+        // Update the type of the function to reflect this new parameter.
+        fixUpFuncType(func);
+
         // The new parameter can be registered as the context value
         // to be used for `func` right away.
         //