[lldb][test] Remove symlink for API tests.

Summary: Moves lldbsuite tests to lldb/test/API.

This is a largely mechanical change, moved with the following steps:

```
rm lldb/test/API/testcases
mkdir -p lldb/test/API/{test_runner/test,tools/lldb-{server,vscode}}
mv lldb/packages/Python/lldbsuite/test/test_runner/test lldb/test/API/test_runner
for d in $(find lldb/packages/Python/lldbsuite/test/* -maxdepth 0 -type d | egrep -v "make|plugins|test_runner|tools"); do mv $d lldb/test/API; done
for d in $(find lldb/packages/Python/lldbsuite/test/tools/lldb-vscode -maxdepth 1 -mindepth 1 | grep -v ".py"); do mv $d lldb/test/API/tools/lldb-vscode; done
for d in $(find lldb/packages/Python/lldbsuite/test/tools/lldb-server -maxdepth 1 -mindepth 1 | egrep -v "gdbremote_testcase.py|lldbgdbserverutils.py|socket_packet_pump.py"); do mv $d lldb/test/API/tools/lldb-server; done
```

lldb/packages/Python/lldbsuite/__init__.py and lldb/test/API/lit.cfg.py were also updated with the new directory structure.

Reviewers: labath, JDevlieghere

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71151

lldb/test/API/python_api/formatters/main.cpp

@@ -0,0 +1,59 @@
+#include <stdio.h>
+#include <vector>
+
+struct JustAStruct
+{
+	int A;
+	float B;
+	char C;
+	double D;
+	long E;
+	short F;
+};
+
+struct FooType
+{
+	int A;
+	float B;
+	char C;
+	double D;
+	long E;
+	short F;
+};
+
+struct CCC
+{
+	int a, b, c;
+};
+
+struct Empty1 { void *data; };
+struct Empty2 { void *data; };
+
+
+int main(int argc, char const *argv[]) {
+	JustAStruct foo;
+	foo.A = 1;
+	foo.B = 3.14;
+	foo.C = 'e';
+	foo.D = 6.28;
+	foo.E = 3100419850;
+	foo.F = 0;
+
+	FooType bar;
+	bar.A = 1;
+	bar.B = 3.14;
+	bar.C = 'e';
+	bar.D = 6.28;
+	bar.E = 3100419850;
+	bar.F = 0;
+	JustAStruct* foo_ptr = &foo;
+
+	std::vector<int> int_vector;
+
+	CCC ccc = {111, 222, 333};
+
+        Empty1 e1;
+        Empty2 e2;
+
+	return 0; // Set break point at this line.
+}