test: disambiguate e2e and perf spec files (#34753)

Currently, based on the file names it's not quite clear whether
a given `.spec.ts` file runs benchmark perf or benchmark e2e
functionality tests. To disambiguate these, we use new file
suffixs. i.e. `e2e-spec.ts` and `perf-spec.ts`.

PR Close #34753

modules/benchmarks/src/largetable/BUILD.bazel

@@ -11,7 +11,7 @@ ts_library(
 ts_library(
     name = "perf_tests_lib",
     testonly = 1,
-    srcs = ["largetable_perf.spec.ts"],
+    srcs = ["largetable.perf-spec.ts"],
     deps = [
         "//modules/e2e_util",
         "@npm//protractor",
@@ -21,7 +21,7 @@ ts_library(
 ts_library(
     name = "e2e_tests_lib",
     testonly = 1,
-    srcs = ["largetable.spec.ts"],
+    srcs = ["largetable.e2e-spec.ts"],
     tsconfig = "//modules/benchmarks:tsconfig-e2e.json",
     deps = [
         "//modules/e2e_util",