Make hipModuleGetGlobal be in HIP runtime so it can be discovered at runtime (#981)

* Make hipModuleGetGlobal be in HIP runtime so it can be discovered at runtime

In HIP PR #929, quite a few HIP public APIs were made as inline functions with
hidden visibility. It was necessary to support applications with shared
libraries with GPU kernels launched via hipLaunchKernelGGL(), after HIP runtime
is initialized.

In empirical tests, the implementation has been proved to be a bit too
excessive, especially for hipModuleGetGlobal(). The function is used by another
type of client applications which relies on the existence of this function
within HIP runtime so global symbols from HSA code objects loaded dynamically
at runtime can be retrieved programmtically.

This commit moves hipModuleGetGlobal() back to src/hip_module.cpp, and makes it
visible and not inline, to fulfill requirements for applications
aforementioned. It does not change the behavior of applications depending on
hipLaunchKernelGGL().

* Add HIP_INIT_API into the implementation of hipModuleGetGlobal

Address review comments.

* Fix failing HIP unit tests

hipamd/src/hip_module.cpp

@@ -282,6 +282,16 @@ hipError_t hipHccModuleLaunchKernel(hipFunction_t f, uint32_t globalWorkSizeX,
         localWorkSizeZ, sharedMemBytes, hStream, kernelParams, extra, startEvent, stopEvent, 0));
 }
 
+hipError_t hipModuleGetGlobal(hipDeviceptr_t* dptr, size_t* bytes,
+                              hipModule_t hmod, const char* name) {
+    HIP_INIT_API(hipModuleGetGlobal, dptr, bytes, hmod, name);
+    if (!dptr || !bytes || !hmod) return hipErrorInvalidValue;
+
+    if (!name) return hipErrorNotInitialized;
+
+    return hip_impl::read_agent_global_from_module(dptr, bytes, hmod, name);
+}
+
 namespace hip_impl {
     hsa_executable_t executable_for(hipModule_t hmod) {
         return hmod->executable;