Rename intrinsic.cc to sem_intrinsic.

For consistency with the other .cc file names in this directory.
The reason we need the sem_ prefix is because all the tint lib code is compiled as a single target, and .GN cannot cope with .cc files with the same file name, even if they're in different directories.
This could be fixed by building each directory as a separate target, but we have circular dependencies that currently make this impossible.

Change-Id: I2f1379ff11dd863f81662449f73d67832f0a8a4e
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/40501
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>

BUILD.gn

@@ -379,7 +379,6 @@ source_set("libtint_core_src") {
     "src/semantic/call.h",
     "src/semantic/expression.h",
     "src/semantic/info.h",
-    "src/semantic/intrinsic.cc",
     "src/semantic/intrinsic.h",
     "src/semantic/node.h",
     "src/semantic/sem_call.cc",
@@ -387,6 +386,7 @@ source_set("libtint_core_src") {
     "src/semantic/sem_expression.cc",
     "src/semantic/sem_function.cc",
     "src/semantic/sem_info.cc",
+    "src/semantic/sem_intrinsic.cc",
     "src/semantic/sem_member_accessor_expression.cc",
     "src/semantic/sem_node.cc",
     "src/semantic/sem_variable.cc",

src/CMakeLists.txt

@@ -193,7 +193,6 @@ set(TINT_LIB_SRCS
   semantic/call.h
   semantic/expression.h
   semantic/info.h
-  semantic/intrinsic.cc
   semantic/intrinsic.h
   semantic/node.h
   semantic/sem_call.cc
@@ -202,6 +201,7 @@ set(TINT_LIB_SRCS
   semantic/sem_member_accessor_expression.cc
   semantic/sem_function.cc
   semantic/sem_info.cc
+  semantic/sem_intrinsic.cc
   semantic/sem_node.cc
   semantic/sem_variable.cc
   semantic/type_mappings.h