Make stack_tracer more broadly usable (#29660)

These changes reduce the stack_tracer's dependencies, allowing it to be
added to other targets such as `gpr_base` without dependency cycles.

Why would I want to do this? printf debugging lock problems that only
occur on the CI's Mac VMs, which we cannot access.

BUILD

@@ -776,6 +776,22 @@ grpc_cc_library(
     ],
 )
 
+grpc_cc_library(
+    name = "examine_stack",
+    srcs = [
+        "src/core/lib/gprpp/examine_stack.cc",
+    ],
+    hdrs = [
+        "src/core/lib/gprpp/examine_stack.h",
+    ],
+    external_deps = [
+        "absl/types:optional",
+    ],
+    deps = [
+        "gpr_platform",
+    ],
+)
+
 grpc_cc_library(
     name = "gpr_base",
     srcs = [
@@ -810,7 +826,6 @@ grpc_cc_library(
         "src/core/lib/gpr/tmpfile_posix.cc",
         "src/core/lib/gpr/tmpfile_windows.cc",
         "src/core/lib/gpr/wrap_memcpy.cc",
-        "src/core/lib/gprpp/examine_stack.cc",
         "src/core/lib/gprpp/fork.cc",
         "src/core/lib/gprpp/global_config_env.cc",
         "src/core/lib/gprpp/host_port.cc",
@@ -833,7 +848,6 @@ grpc_cc_library(
         "src/core/lib/gpr/string_windows.h",
         "src/core/lib/gpr/time_precise.h",
         "src/core/lib/gpr/tmpfile.h",
-        "src/core/lib/gprpp/examine_stack.h",
         "src/core/lib/gprpp/fork.h",
         "src/core/lib/gprpp/global_config.h",
         "src/core/lib/gprpp/global_config_custom.h",
@@ -870,6 +884,7 @@ grpc_cc_library(
     deps = [
         "construct_destruct",
         "debug_location",
+        "examine_stack",
         "google_rpc_status_upb",
         "gpr_codegen",
         "gpr_tls",

test/core/util/BUILD

@@ -171,7 +171,8 @@ grpc_cc_library(
     ],
     language = "C++",
     deps = [
-        "//:grpc_common",
+        "//:examine_stack",
+        "//:gpr_platform",
     ],
 )