Remove LLVM 7.0 git submodule

LLVM 7.0 will be added back as a subtree instead.

This reverts commit 1841c50cf0abab2a6d7b5e86b614fbcace7d57f7.

Bug b/115344057

Change-Id: I5fc51be1f107f3de0e97e8b53e282b0cc9557bed
diff --git a/.gitmodules b/.gitmodules
index d80c7e2..5a4e85a 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,6 +1,3 @@
 [submodule "third_party/googletest"]
 	path = third_party/googletest
 	url = https://github.com/google/googletest.git
-[submodule "third_party/llvm-7.0/llvm"]
-	path = third_party/llvm-7.0/llvm
-	url = https://git.llvm.org/git/llvm.git
diff --git a/third_party/llvm-7.0/llvm b/third_party/llvm-7.0/llvm
deleted file mode 160000
index 98aa61b..0000000
--- a/third_party/llvm-7.0/llvm
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 98aa61ba49b54902a7afc27c9aa6c562646be76f