Remove the vendored copy of TSC (#2991)

Author: neonichu

Package.swift

@@ -306,7 +306,7 @@ if ProcessInfo.processInfo.environment["SWIFTCI_USE_LOCAL_DEPS"] == nil {
     ]
 } else {
     package.dependencies += [
-        .package(path: "./swift-tools-support-core"),
+        .package(path: "../swift-tools-support-core"),
         .package(path: "../swift-argument-parser"),
         .package(path: "../swift-driver"),
     ]

Utilities/bootstrap

@@ -167,7 +167,7 @@ def parse_global_args(args):
     """Parses and cleans arguments necessary for all actions."""
     args.build_dir = os.path.abspath(args.build_dir)
     args.project_root = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-    args.tsc_source_dir = os.path.join(args.project_root, "swift-tools-support-core")
+    args.tsc_source_dir = os.path.join(args.project_root, "..", "swift-tools-support-core")
     args.yams_source_dir = os.path.join(args.project_root, "..", "yams")
     args.swift_argument_parser_source_dir = os.path.join(args.project_root, "..", "swift-argument-parser")
     args.swift_driver_source_dir = os.path.join(args.project_root, "..", "swift-driver")