[spirv-reader] Support function calls, except returning void

Functions returning void are blocked on https://crbug.com/tint/45

Change-Id: I15ec9cf0e267571bbfab921c678a59e25d0e3619
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/25280
Reviewed-by: dan sinclair <dsinclair@chromium.org>
diff --git a/BUILD.gn b/BUILD.gn
index 67d7557..1c0b35a 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -729,6 +729,7 @@
     "src/reader/spirv/fail_stream_test.cc",
     "src/reader/spirv/function_arithmetic_test.cc",
     "src/reader/spirv/function_bit_test.cc",
+    "src/reader/spirv/function_call_test.cc",
     "src/reader/spirv/function_cfg_test.cc",
     "src/reader/spirv/function_composite_test.cc",
     "src/reader/spirv/function_conversion_test.cc",