tests: clean up bad extension
The presence of the "babar" extension breaks subsequent tests.
So delete the file and create an empty one to return the config
to sanity.
hgterm,
am, km, mir, msgr, xenl,
colors#8, cols#80, it#8, lines#24, pairs#64,
acsc=``aaffggiijjkkllmmnnooppqqrrssttuuvvwwxxyyzz{{||}}~~,
bel=^G, bold=\E[1m, clear=\E[H\E[2J, cr=\r,
csr=\E[%i%p1%d;%p2%dr, cub=\E[%p1%dD, cub1=\b,
cud=\E[%p1%dB, cud1=\n, cuf=\E[%p1%dC, cuf1=\E[C,
cup=\E[%i%p1%d;%p2%dH, cuu=\E[%p1%dA, cuu1=\E[A,
dch=\E[%p1%dP, dch1=\E[P, dl=\E[%p1%dM, dl1=\E[M,
ed=\E[J, el=\E[K, enacs=\E)0, home=\E[H, ht=\t,
hts=\EH, il=\E[%p1%dL, il1=\E[L, ind=\n,
is2=\E[m\E[?7h\E[4l\E>\E7\E[r\E[?1;3;4;6l\E8, kbs=\b,
kcub1=\EOD, kcud1=\EOB, kcuf1=\EOC, kcuu1=\EOA,
kdch1=\E[3~, kf1=\E[11~, kf10=\E[21~, kf11=\E[23~,
kf12=\E[24~, kf13=\E[25~, kf14=\E[26~, kf15=\E[28~,
kf16=\E[29~, kf17=\E[31~, kf18=\E[32~, kf19=\E[33~,
kf2=\E[12~, kf20=\E[34~, kf3=\E[13~, kf4=\E[14~,
kf5=\E[15~, kf6=\E[17~, kf7=\E[18~, kf8=\E[19~,
kf9=\E[20~, kfnd=\E[1~, kich1=\E[2~, kmous=\E[M,
knp=\E[6~, kpp=\E[5~, kslt=\E[4~, op=\E[m, rc=\E8,
rev=\E[7m, ri=\EM, rmacs=^O, rmcup=\E[2J\E[?47l\E8,
rmir=\E[4l, rmkx=\E[?1l\E>, rmso=\E[m, rmul=\E[m,
rs2=\E[m\E[?7h\E[4l\E>\E7\E[r\E[?1;3;4;6l\E8, sc=\E7,
setab=\E[4%p1%dm, setaf=\E[3%p1%dm, sgr0=\E[m,
smacs=^N, smcup=\E7\E[?47h, smir=\E[4h,
smkx=\E[?1h\E=, smso=\E[7m, smul=\E[4m, tbc=\E[3g,
u6=\E[%i%d;%dR, u7=\E[6n, u8=\E[?1;2c, u9=\E[c,