Write tests for new APE loader and fix bugs

- Add FreeBSD-specific mmap() flags
- Reduce size of the APE loader from 8kb to 4kb
- Work towards fixing the Makefile build on WSL
- Automate testing of APE no-modify-self behaviors
- Make the ape.S shell script code cleaner and tinier
- Improve the APE sanity check to test behavior better
- Fixed issue with ShowCrashReports() sigaltstack() on BSDs
- Delete symbols for S_MODE magnums which wasted compile time

If you checked out yesterday's APE commit, please run:

    rm -f /usr/bin/ape o/tmp/ape /tmp/ape "${TMPDIR:-/tmp}/ape"

Because this change fixes certain aspects of the new ABI. We don't have
automated migrations for APE loader versions yet. Thanks! You can also
download prebuilt binaries here:

- https://justine.lol/ape.elf    (Linux/FreeBSD/NetBSD/OpenBSD)
- https://justine.lol/ape.macho  (Apple)

Install the appropriate one as `/usr/bin/ape`.

test/libc/release/test.mk

@@ -9,7 +9,15 @@ o/$(MODE)/test/libc/release/cosmopolitan.zip:			\
 		o/$(MODE)/ape/ape-no-modify-self.o		\
 		o/$(MODE)/cosmopolitan.a			\
 		o/$(MODE)/third_party/zip/zip.com
-	@$(COMPILE) -AZIP -T$@ o/$(MODE)/third_party/zip/zip.com -qj $@ o/cosmopolitan.h o/$(MODE)/ape/ape.lds o/$(MODE)/libc/crt/crt.o o/$(MODE)/ape/ape.o o/$(MODE)/ape/ape-no-modify-self.o o/$(MODE)/cosmopolitan.a
+	@$(COMPILE) -AZIP -T$@					\
+		o/$(MODE)/third_party/zip/zip.com		\
+		-qj $@						\
+		o/cosmopolitan.h				\
+		o/$(MODE)/ape/ape.lds				\
+		o/$(MODE)/libc/crt/crt.o			\
+		o/$(MODE)/ape/ape.o				\
+		o/$(MODE)/ape/ape-no-modify-self.o		\
+		o/$(MODE)/cosmopolitan.a
 
 o/$(MODE)/test/libc/release/smoke.com:				\
 		o/$(MODE)/test/libc/release/smoke.com.dbg