Fix broken -emit-spirv-via-glsl test option (#7091)

Fixes issue #6898

The -emit-spirv-via-glsl slang-test option has been broken for
some amount of time. Tests that were using it were operating as
if using -emit-spirv-directly, leading to many duplicated tests.

After fixing the test option, there were an number of errors that
appeared as a result.

This change fixes the broken test option and the resulting test
errors. Some of the test errors revealed some legitimate issues,
such as:

-The GLSL bitCount instrinsic only supports 32-bit integers and
 requires emulation for other bit widths.
-Emitting GLSL 8-bit and 16-bit glsl integer types did not emit
 the proper extension requirements
-Emitting GLSL and casting for 16-bit integers was missing a
 closing parenthesis.
-Missing profile for GL_EXT_shader_explicit_arithmetic_types
-Missing toType cases for UInt8/Int8 for the kIROp_BitCast case
 in tryEmitInstExprImpl.

1 files changed, 1 insertions, 0 deletions

diff --git a/docs/command-line-slangc-reference.md b/docs/command-line-slangc-reference.md
index 1562ce02f..296441a2e 100644
--- a/docs/command-line-slangc-reference.md
+++ b/docs/command-line-slangc-reference.md
@@ -1226,6 +1226,7 @@ A capability describes an optional feature that a target may or may not support.
 * `GL_EXT_shader_atomic_float_min_max` : enables the GL_EXT_shader_atomic_float_min_max extension 
 * `GL_EXT_shader_atomic_float2` : enables the GL_EXT_shader_atomic_float2 extension 
 * `GL_EXT_shader_atomic_int64` : enables the GL_EXT_shader_atomic_int64 extension 
+* `GL_EXT_shader_explicit_arithmetic_types` : enables the GL_EXT_shader_explicit_arithmetic_types extension 
 * `GL_EXT_shader_explicit_arithmetic_types_int64` : enables the GL_EXT_shader_explicit_arithmetic_types_int64 extension 
 * `GL_EXT_shader_image_load_store` : enables the GL_EXT_shader_image_load_store extension 
 * `GL_EXT_shader_realtime_clock` : enables the GL_EXT_shader_realtime_clock extension